(1) Field of the Invention
The present invention relates to a rectifier, and particularly to a rectifier of a power supply which can be used to a switching power supply (SPS).
(2) Description of the Prior Art
With the improvement of electronic technology, the sizes of the products are made smaller and smaller, thereby, the space for receiving a power source becomes smaller. This induces many problem, such as power consumption, efficiency, stability, etc. The power rectifying is important for above mentioned problems since a well rectifying ability will improve the problem of power consumption, efficiency and stability.
Switching power supplies (SPS), as shown in FIG. 1, are frequently used in current electronic device. When current flows through the transformer 10 and then is sent to a rectifier formed by a rectifying device 11 and a fifth capacitor 135. Then the current is transferred to the power output end VO. The rectifier 11 is made of diodes which makes a large power lose. In another prior art, the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is used to replace a diode since the current waveform can not generate a delay time so that the delay time makes a larger power loss. Therefore, since the synchronization of the current waveform can not be achieved and thus the whole power loss of the switching power supply (SPS) can not be greatly improved.
Accordingly, the primary object of the present invention is to provide a rectifier of a power supply. The rectifier comprises a delay unit at a front end of a circuit for delaying a transient variation of a power current and then delaying the current to a rectifying end; a driving unit coupling to the delay unit by two inductors for adding an inducting voltage to a voltage of a switch unit at an input end for being converting as a driving voltage and for emitting a state of the driving unit based on a waveform of the driving voltage; and the switch unit being connected to the driving unit for receiving the state of the driving unit and for conducting or cutting-of the power current so that the operation of the switch unit is synchronous with the waveform of the power current.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.